# A Journey in Other Worlds HTML version

Preparing To Alight
That afternoon Ayrault brought out some statistical tables he had compiled from a great
number of books, and also a diagram of the comparative sizes of the planets. "I have been
not a little puzzled at the discrepancies between even the best authors," he said, "scarcely
any two being exactly alike, while every decade has seen accepted theories radically
changed." Saying which, he spread out the result of his labours (shown on the following
pages), which the three friends then studied. ------------------------------------------------------
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(1) Mean distance from sun in millions of miles
(2) Semimajor axis of orbit, earth's distance as 1
(3) Eccentricity of orbit
(4) Planets inclination of orbit to elliptic
(5) Light at perihelion
(6) Light at apehelion
(7) Heat, earth as 1
(1) (2) (3) (4) (5) (6) (7)
Mercury... 36.0 0.387 0.2056 7@0'8" 10.58 4.59 6.67
Venus..... 67.2 0.723 0.0068 3@23'35" 1.94 1.91 1.91
The Earth. 92.9 1.000 0.068 0@0'0" 1.03 0.997 1.00
Mars......141.5 1.524 0.0933 1@51'2" 0.52 0.360 1.43
Asteroids 204.4 to 2.200 0.4 to 5@-35@ 325.2 to 3.500 0.34
Jupiter.. 483.3 5.203 0.0483 1@18'41" 0.04 0.034 0.037
Saturn... 886.0 9.539 0.0561 2@29'40" 0.012 0.0099 0.011
Uranus.. 1781.9 19.183 0.0463 0@46'20" 0.0027 0.0025 0.003
Neptune. 2791.6 30.055 0.0090 1@47'2" 0.0011 0.0011 0.001
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(1) MOVEMENT IN ORBIT. Velocity compared with earth as 1.
(2) MOVEMENT IN ORBIT. Period of revolution in years and days.
(3) MOVEMENT IN ORBIT. Orbital velocity in miles per second.
(4) Mean diameter in miles
(5) Surface compared with earth as 1.
(6) Volume compared with earth as 1.
(7) Mass compared with earth as 1.
Planets (1) (2) (3) (4) (5) (6) (7)
Mercury..... 0.88 23 to 35 1.6 3,000 0.14 0.056 0.13
Venus.....0.224 1/2 21.9 1.17 7,700 0.94 0.92 0.78
The Earth... 1.00 18.5 1.0 7,918 1.00 1.00 1.00
Mars........ 1.88 15.0 0.81 4,230 0.28 0.139 0.124
Asteroids... 3.29 .... .... From a few to 6.56
miles to 300
Jupiter..... 11.86 8.1 0.44 86,500 118.3 1309.00 316.0
Saturn...... 29.46 6.0 0.32 1,000 0.4 760.0 95.0
Uranus...... 84.02 4.2 0.23 31,900 16.3 65.0 14.7
Neptune.... 164.78 3.4 0.18 34,800 19.3 90.0 17.1
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(1) Length of day. hrs. min. sec.
(2) Length of seasons
(3) DENSITY Compared with earth as 1
(4) DENSITY Compared with water as 1
(5) FORCE OF GRAVITY AT SURFACE OF PLANET Compared with earth as 1.
(6) FORCE OF GRAVITY AT SURFACE OF PLANET Bodies fall in one second.